Roof Sheathing, Loft Framing, and More

We finished the roof sheathing! As I feared, we had to use an extra piece of plywood. It wasn't the most efficient job ever. But it's done!

But what's more exciting is that we have now started the interior framing--and closed up the wheel wells, too.








Interior Framing: Lofts

There are two lofts in my tiny house: the 5' 6" wide living room loft, above my bed alcove, and the 3' 1" wide storage loft, above the bathroom. Both span the whole width of the house.

Bolt (from the outside)

I've chosen to attach the loft floors to the walls with 1/2" bolts that pass all the way through the SIP wall, from outside in. Those bolts hold a 2x6 ledger board to the wall, and the 2x6 joists of the loft floors hang off the ledger board. That way whatever weight is on the loft floor will be distributed through the whole wall, not hanging off a single SIP skin (which, remember, is only attached to the foam with a layer of adhesive). I used construction adhesive to reinforce the attachment.

(Another way to install a loft in a SIP tiny house is to cut holes in the inner SIP skin, excavate a 2x6-shaped hole in the foam, and slide the joists in. My intuition said that the bolts would compromise the structure and insulation less. However, the bonafide engineer whose SIP tiny house I visited the other day used the hole-in-the-SIP method, so... hmm...)

Because of the bolts, the loft ledger boards should be installed before we can wrap the house in Tyvek, and the house has to be wrapped in Tyvek before almost anything else can happen to the exterior--and before it's safe from wet weather. We've had a gloriously sunny spring so far, but it's only a matter of time...!

So we installed the larger loft ledger boards on Tuesday, and on Wednesday we installed the storage loft ledger boards.

But before I show you the storage loft, I want to show you what I did to the big loft framing. It'll be exposed to view, so I didn't want to leave the Douglas fir lumber all naked and pink (yup, pink). So yesterday, I took a hand-held propane torch and very, very carefully gave the wood a touch of... you guessed it, my new favorite wood treatment ever...: shou sugi ban!

Before shou sugi ban...

After shou sugi ban

Shou sugi ban is so awesome. It's like painting, but with fire. Hee hee!

 Since I didn't want to mess with scrubbing and rinsing, I went over the wood very lightly--just enough to give it a "tiger stripe" effect. The wood burns in this cool pattern because the soft earlywood (spring growth) in the grain burns faster than the dense latewood (fall/winter growth). I noticed that the knots, where branches originated in the tree's trunk, burned slowly like the latewood. I didn't want big bright spots, though, so I gave the knots an extra blast of flame to darken them.

"Tiger stripe" shou sugi ban effect

Gorgeous, huh?

Don't worry, I had water on hand in case things went south. I did a pretty good job of not toasting the OSB, too!

Storage loft/bathroom ceiling

But back to the storage loft. This loft doubles as the bathroom ceiling, so it's my first physical demonstration of how large the bathroom will be. And hey... I think it's going to be wide enough.

Whew!

Joists on ~18" centers

 

 I'm not really sure at this point what I'll be storing in this storage loft, but I do know that I'll be hiding the ugly stuff--ventilation ducts and the hot water heater--in it. I'll probably keep a box of stuff that I don't use much but can't bear to get rid of (yet), and things like luggage and camping gear.



Wheel Wells

Wheel well sheathing cut to fit behind the fender flashing

The other fun little project has been closing in the wheel wells. We had to finish this, too, before Tyvek time; it's the last piece of exterior wall sheathing.

Since I chose to build rectangular wheel well arches over the trailer's curved fenders, something has to fill the gap that was left. Plywood is that something. I'm using the same grade of plywood--CDX (i.e. ugly on one side, uglier on the other side, and rated for weather exposure)--that I used for the roof sheathing, subfloor, and undercarriage.

We weren't sure whether we could make the curved cuts without a jig saw--yes, jig saw as in jigsaw puzzle (ever wonder how they cut out those intricate little shapes? Well... lasers, nowadays)--but the circular saw actually worked fine, for an edge that won't be visible.

Ideally, those curved plywood pieces will fit behind the built-in fender flashing, then the Tyvek will cover both, creating a layering of weatherproof material that won't allow any water to come in contact with the plywood or infiltrate into the wheel well boxes. This idea situation will be the case on one side of the house; on the other side, the wall somehow came too close to the edge of the flashing, so we had to layer the plywood in front of the flashing, not behind. The interior will still be protected from leaks by the flashing, but I'll have to come up with another arrangement to prevent water from dripping onto the fender and wetting the plywood.

With the possibility of wet plywood in mind, before we installed the pieces, Dad thought it would be a good idea to paint the edges that will be in contact with the metal. This will help ward off water damage and decay, in case there is any condensation or (heaven forfend!) leakage in this rather vulnerable area.

We glued and screwed these pieces in place--patting myself on the back for leaving a nice, wide attachment surface when I built the wheel well arches--and now we're ready for Tyvek!